Mechanical Solutions Case Studies
See How We Prevent, or Pinpoint and Resolve, Difficult Vibration and Dynamics Problems.
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How a Large Water Treatment Plant Truly Solved Their Rotating Machinery Problem
This in-depth case study presents a detailed process to identify and resolve a vertical turbine pump resonance issue, including pump troubleshooting methodology and engineered fixes.
Reduce Vibration and Acoustic Risk At 60% Plant Design With Evaluation (CWP)
The Civil Engineers at a major Architect/Engineering firm used MSI’s experience and modern methodology to reduce the risk of future schedule- and budget-killing contractor change orders caused by vibration problems.
Boiler Feed Pump Optimization to Reduce Cavitation
Accurate CFD modeling, validated by real-world results, provides the basis for a redesigned impeller that significantly reduces cavitation. This example models the first stage of a boiler feed pump.
Super-Synchronous Vibration in a Single Stage Overhung Centrifugal Pump
A pump manufacturer needed help identifying a super-synchronous vibration issue of a unit on the test stand. The manufacturer was trying to understand why the pump system was experiencing varying vibration levels at four different test locations.
Turbine Vibration: A Cure For The Common Cold
A 45 MW steam turbine at a waste-to-energy facility in the Northeast underwent a scheduled repair, at which time the turbine bearings were reworked. After this rework, the turbine periodically experienced very high amplitude shaft vibrations.
Predicting Resonance in a Reciprocating Pump
MSI engineers performed a torsional analysis of a reciprocating pump/gear/motor system being designed for a large overseas petroleum drilling venture. Analysis of the initially designed system indicated that there was a possibility of resonant torsional vibration, driven by 50 Hz line frequency.
Elimination of Super-Synchronous Pump Vibration
MSI was contacted by a large U.S. pump OEM to perform specialized vibration testing of a single-stage centrifugal pump at their main development facility. Destined for a large petroleum refinery, the double-suction pump would be subject to coke formation in vacuum bottoms service.
Nuclear Service Water Pump Elevated Vibration
Four nuclear Service Water (SW) pumps had been retrofitted to use a modified below-ground structure. After several years of operation, one of the SW pumps experienced vibration at twice normal levels at the below-ground submersible accelerometers. This high vibration condition began after the rotating top shaft sleeve was replaced to address excessive top shaft radial motion.
Water Filtration Plant Energy Dissipation Valve Vibration
Energy Dissipation Valves (EDVs) at a water filtration plant were exhibiting high vibration amplitude at the piping/ elbow down-stream from the EDV. The newly installed water filtration plant had been designed to dissipate a differential static head of treated water at approximately 155 ft elevation, from high service water at approximately 290 ft of elevation (~50 psig).
Fixing Resonance In A Submersible Dry Pit Pump System
Four recently installed vertically mounted, variable speed driven non-clog pumps were suffering from high vibration. In one case, the concrete support piers exhibited cracking damage. MSI was contracted to perform specialized field testing and analysis to characterize the problem. Finite Element Analysis (FEA) was used to design an effective solution.
Dramatic Ring-Section Pump Vibration Improvement Using ODS
MSI's ODS testing suggested modifications for the baseplate of a Boiler Feed Pump that greatly reduced the max vibration amplitude at the outboard bearing housing, solving the problem.
Operating Deflection Shape (ODS) Testing Uncovers a Turbine Disk Resonance
MSI conducted vibration testing of a rerated medium power steam turbine in US-Mideast on December 2015. The main purpose of the testing was to evaluate a potentially resonant bladed disk vibration of the control stage within a specified speed range.
Design Optimization of a High Speed Motor-Driven Centrifugal Compressor
Challenge: Design a centrifugal compressor for use in blower applications.Results: An efficient compact design.Impact: High efficiency design achieves compression at reduced power.
Raw Water Pumps Experience High Vibrations and Failures
It was reported by a construction company that four raw water vertical turbine pumps had severe vibration issues as well as catastrophic failures since the water treatment plant was placed into service in September 2010. MSI was called to help at the end of April 2015.
Design Optimization of a Low Pressure Steam Turbine Stage
A turbine end-user wanted to optimize the performance of one of his turbines, and submitted the last stage of his steam turbine for analysis and optimization. The stage was analyzed using CFX software which employed real gas properties in order to correctly model the thermodynamic properties of steam.
Fluid Drive Troubleshooting Of A Boiler Feed Pump
A boiler feed pump (BFP) driven off of the main steam turbine via a fluid drive was experiencing high vibration levels leading to frequent replacement of the fluid drive bearings. The plant depended on the single BFP for power production.
Gear Box Vibration
MSI was contracted by the OEM to perform testing and analysis to determine the root cause of gear tooth failures on an aeroderivative gas turbine power generation drivetrain. The 37 MW gearbox had broken pinion teeth after several thousand operating hours.
Compressor Vibration Caused By Rotor Instability In An Integrally Geared Unit
MSI was called in by an end-user to help troubleshoot a newly commissioned critical compressor train experiencing unexplained vibration trips. These sudden vibration trips threatened to jeopardize delivery of product and thereby result in a substantial loss of revenue.
Resonance – Small Bore Pipe Vibration at a Pumping Station
This case study looks at a nagging problem within the pipeline industry - small bore piping resonance, and shows how to solve it with video vibration tools.
Fluid – Thermal Finite Element Analysis of a Printed Circuit Board
A computer circuit board with a high clock speed processor chip was analyzed in an effort to establish the effectiveness of the cooling system. Processor chips can run too hot and their performance can deteriorate as a result. Different geometries for heat sinks and cooling fan locations can be analyzed in order to optimize chip cooling performance.
Design of Oil Extraction Gear Pump & Motor
MSI was contracted to design a down-hole, multi-set external gear hydraulic motor – pump unit. The system had to meet specific requirements to achieve a design to replace the current pitot jet-pump configuration.
Assess Foundation Effects on Existing Solids Handling Pumps
An example demonstrating the impact of the foundation in pre-installation natural frequency analysis. In this case, by determining the effect of the foundation on the natural frequencies of the currently installed pumps, the importance of including the flooring/foundation in future FEA analysis predictions for the new pumps could be quantified.
Sub-Synchronous Vibration in a Reverse Osmosis Membrane Vertical Turbine Pump
A construction firm needed help in determining the root cause for the high vibration amplitude of the above-ground structure on four out of six newly installed pumps and provide a solution to mitigate this issue. These new pumps were part of a plant expansion project to increase water capacity.
Premature Bearing Failures in Nuclear Bus Duct Cooling Fans
A nuclear power plant had changed bus duct cooling fan bearings approximately five times in two years. The plant wanted to find the root cause of the failures so they could address the main problem instead of changing out bearings more frequently. The increased replacement frequency brought increased cost and unscheduled maintenance.
Stress Analysis of a Total Hip Replacement
The longevity of a total hip arthroplasty depends on many factors. Often times the weakest link in the system is the cement mantle that fixes the metal hip stem to the surrounding bone. In an effort to combat this, a hip stem manufacturer came to MSI to develop a better understanding of the effect of their hip stem design on the cement mantle stress distribution and to find ways to improve it.
Design, Analyze, and Build a Prototype Radial Gas Turbine
MSI was tasked with designing a prototype high speed radial gas turbine to operate at 40,000 RPM with R-134a as the working fluid. The goal was to produce 20 HP with a compact turbine and integrated generator unit.
Nuclear Generator Stator Cooling Pumps Specialized Vibration Testing
A nuclear power plant’s generator stator cooling pumps had experienced random elevated vibrations during steady conditions since their installation in the 1980s. These typical vibration issues required fine tuning of the alignment to reduce the vibration down to acceptable levels after every outage.
Design Exploration For A Centrifugal Pump Design
This is a case study of an automated CFD design exploration for a centrifugal pump impeller with CFturbo and STAR-CCM+.
Vibration on Centrifugal Compressors
In general, MSI’s role in helping to ensure equipment reliability takes place at three levels: (a) preconstruction assessments and analysis during the design phase to help prevent problems, (b) using specialized testing and analysis techniques to solve performance, acoustic, vibration, stress, or thermal problems before failure takes place, and (c) performing root cause analysis (RCA) after a failure.
Upgraded Pump Station Exceeds Overall & Pipe Vibration Limits
A recently upgraded pipeline crude oil pump station in Texas was experiencing high vibration levels on its pumps. MSI set out to diagnose these VFD controlled units.
Automated Design Optimization of a Hydroturbine
This case study examines the powerful integrated capabilities between the turbomachinery design tool CFturbo and the computational fluid dynamics analysis tool STAR-CCM+ to produce an automated design of experiments, achieving optimized performance for a hydroturbine.
Design Assessment Mitigates Risk
A design assessment was carried out in an effort to prevent potential premature bladed disk and impeller fatigue failures of three newly installed critical compressor trains. Such a failure would result in a minimum five day pre-mature repair shutdown and cause over $15M (USD) in lost production revenue to the End User.
Failure Analysis of a Reciprocating Pump Valve
An offshore rig septuplex pump was experiencing chronic suction and discharge valve failures. A more robust valve design implemented by the manufacturer did not solve the problem. MSI engineers performed test stand and on-rig pulsation and vibration testing.
Resonant Room Acoustics Exciting Destructive Vibration at a Nuclear Power Plant
The 4kV switchgear cabinets at a nuclear power facility were experiencing reliability issues, seemingly due to shaking at the frequency of the turbine/ generator mounted on the deck above. Oddly, the floor of the switchgear cabinets had an extremely low level of vibration at the frequency in question, so was not the apparent source of the vibration.
Assess Water Level Effects On 5-Stage Vertical Turbine Pumps (VTP)
An example demonstrating the impact of the water level in pre-installation natural frequency analysis. By taking a system-level approach and performing the analysis at both the high water level (HWL) and low water level (LWL) station conditions, MSI was able to predict a potential resonance problem with the 2nd below-ground pump bending mode within the 1x pump RPM range at the LWL condition. The pump manufacturer was then able to make design changes before building the pump to avoid installing potential resonance and vibration issues.
Designing an Oscillating Water Column Wave Energy Converter
In this MSI turbomachinery design for innovator Wave Swell Energy, wave energy is converted to electricity with air. MSI helped bring the idea from concept to reality.
New Orleans Flood Control Pumping Stations Vibration Analysis
In response to the flood damage to New Orleans by Hurricane Katrina, the U.S. Army Corps of Engineers Hurricane Protection Office awarded a design and build contract to a new prime contractor in 2007. The goal was to increase the pumping capacity at the 17th Street and London Avenue canals, allowing for future worst case hurricane drainage to be pumped out of the city and into Lake Pontchartrain.
Vibration Testing of Two Induced Draft Fans
Mechanical Solutions, Inc. (MSI) was contracted by a power generation company to solve excessive vibration problems on two newly installed Induced Draft (ID) fans. High vibration levels at one times (1x) running speed were reported that exceeded trip levels during start-up. Traditional vibration analysis used by others had not successfully resolved what initially appeared to be a straight-forward unbalance and/or misalignment problem.
UREA Screener Failure Problems
MSI was contracted by a major South American petrochemical plant to perform detailed vibration tests and FEA modal and stress analysis on a Urea Vibrating Screener. The screener had been suffering periodic failures due to cracks along the welds, plates, and structural beams, as well as hanger wire failures since installation in 1999.
Closed Cooling Water Glycol Pump Skid Flow & Vibration Issues
The construction company of a natural gas powered electric generating facility was trying to understand why they were measuring a significant flow difference between field and factory test pump curves on the closed cooling water pump skid. MSI was contracted to diagnose the flow difference and perform a vibration inspection.
Sudden Vibration Step Changes in Proximity Probe Readings from a Nuclear Feedwater Pump
A nuclear power plant needed help identifying the source of sudden vibration step changes of a cyclic nature from a feedwater pump. This vibration issue only occurred on one of the two proximity probes, which led to MSI being called for assistance.
Remote Vibration Performed In SE Asia Steam Turbine From The USA
A South East Asian power plant was experiencing high vibration and cracking in the exhaust hood of one of its steam turbines. The typical troubleshooting approach is to travel to the site of the machinery, collect the data, analyze it at the home office, and provide a specific solution. However, in order to meet the customer’s timing, technical, and other requirements, MSI agreed to implement a new remote problem solving approach.
Shifting a Natural Frequency Away from Running Speed
A Middle East power plant had a serious 1X running speed vibration problem with some vertical turbine pumps (VTP) for service water and associated piping. Although these pumps were not central to the production of power, the plant could not run for extended periods without them, and motor bearing and discharge head mechanical seal problems were causing chronic pump shut-downs.
Solids Handling Pump Repetitive Failure of Bearing and Seal
An engineering construction firm needed help in determining the root cause for the repetitive pump bearing and seal failures of a solids handling pump and to provide a solution to eliminate the issue. The new pumps were installed to increase the capacity of the wastewater facility.
Hydro Turbine Gearbox Failure Analysis and Repair
When a hydro turbine gearbox failed, MSI was brought in to determine the extent of the damage and provide an engineered solution to get the turbine generating power as quickly as possible.
Circulation Water Pumps Exceed ANSI HI 9.6.4 Vibration Limit
The largest combined-cycle natural gas-fired power facility in Canada (2015) was measuring excessive vibration on two single stage circulation water pumps (CWP). The vibration levels were just below specification requirement upon installation, but over time, the vibration increased by almost a factor of 10.
Curing Resonance in Reactor Feed Pumps
A newly constructed European nuclear power plant had all of its main feed pumps exhibiting vibration on the bearing housings in excess of the vibration specifications, by up to a factor of three, depending upon operating load. Nearly all of the vibration was at vane passing frequency.
Replacing a Pressure Reducing Valve with a Hydro Turbine for a Municipal Water Supply
A municipality receiving its water supply from a high elevation spring sought to replace an energy wasting pressure reducing valve with a hydro turbine. MSI was tasked with designing the turbine to capture power over a challenging range of operating conditions.
Casing Structural Analysis Reduces Risk
Mechanical Solutions, Inc. (MSI) performs pump casing structural analysis typically under contract from pump manufacturers. The starting point includes drawings or solid models, materials of construction information, operating conditions, and a discussion about any unusual concerns or issues.
Nuclear Plant has Identical Motor Generator Sets Vibrating Differently
Two identical MG sets used in a nuclear plant were vibrating differently, one above allowable limits. MSI performed field testing to discover that the rubber mounts were at fault and an immediate shut down was avoided.
Redesign of Oil Industry Multistage Vertical Pump
Challenge: Reduce the number of stages required to perform duty for a multistage vertical pump. Results: Impeller modification and de-swirl vane change. Impact: Increased efficiency and head production per stage, reducing the total stages required resulting in significant savings in production.
Heat Transfer Analysis of a Liquid Cooled Rocket Engine Assembly
This case study demonstrates advanced Computational Fluid Dynamics (CFD) modeling for conjugate heat transfer of a liquid cooled rocket engine.
Solving an ACC Fan Guard Frame Cracking Problem
A newly installed Air Cooled Condenser (ACC) fan guard or screen at an 1100 MW electric power generating station had a failure where plates (bat wings) connect the guard to the fan ring (shroud) structure(Figure 1). The failure occurred after approximately 80 hours of operation.
Blower & Fan Performance Testing Overview
MSI performs laboratory methods of testing fans for certified aerodynamic performance rating. Below are examples and a description of our test facility capabilities.
MSI’s Framework for Fluid Structural Interaction Analysis
Many of the most demanding challenges in turbomachinery system development are related to the prediction of the interacting effect between fluid loads, thermal loads, structural deflection, and the operating points. By providing an integrated framework for turbomachinery analysis, MSI has reduced the time and complexity of the multiphysics analyses.
Reconciling Predicted Hydro Turbine Results to Test Stand Performance
A new hydropower design was tested by the customer, with actual test stand results significantly lower than the customer’s predicted performance. MSI was tasked with resolving the discrepancy, either by determining the flaw in the testing apparatus/procedure, or by correcting the computer model to better represent actual performance.
Contact Stress Analysis of an Artificial Knee
The longevity of an artificial knee replacement depends on many factors. Although great strides have been made in improving the wear performance of ultra-high-molecular-weight polyethylene (UHMWPE), tibial insert wear is still one of the most important failure mechanisms. To improve the wear characteristics,
Rotordynamic Analysis Of A Multi-rotor Gas Turbine
An area of concern for gas turbine OEM’s and end users is the effect of casing and structural supports on the rotordynamic response of multi-rotor systems. MSI has conducted sophisticated analysis of such problems utilizing the latest technology available in Finite Element Analysis (FEA) and rotordynamics.
Pre-Construction Analysis for Singapore's Marina Barrage
Marina Barrage is part of a comprehensive flood control system to eliminate flooding disasters in Singapore. The two-fold responsibility of Mechanical Solutions, Inc. (MSI) was to ensure that: a) the flood control motors, gearboxes, and pumps would not have any life-limiting vibration problems; and b) the pump systems would not cause vibration in the pump house and adjoining visitor’s center including annoying window vibration when the pumps were operational.
Eddy Current Drum Coupled Motor High Vibration Analysis
After being refurbished, the motors experienced excessive vibration at certain pump speeds, thereby restricting the pumping system’s ability to handle various flow ranges. A permanent fix was sought out since pump rental costs significantly increased the cost of operating the pump station.
Troubleshooting a Pipeline Renewable Diesel Screw Pump
Elevated vibration levels were causing a pipeline company screw pump problems. Field tests were conducted to diagnose the cause and propose a solution to the problem.
Steam Turbine Generator Lift Oil System Failure Solution
A nuclear power generating station was looking for answers after both main steam turbine generator trains lost their bearing lift oil systems after each experienced the failure of a one inch oil supply pipe. MSI was contracted to investigate the failures, find the root cause, and develop a solution to prevent future failures.
Resonance in a Nuclear Charge Pump
A nuclear power plant encountered a sudden high vibration problem with one of two motor driven charge pumps. The plant decided to have MSI perform specialized testing and analysis to determine the problem root cause and a solution rather than tearing down the pump for inspection.
Water Treatment Plant Pumps Fail Vibration Specification During Commissioning
A contractor putting together a water treatment facility for a large city in Colorado encountered vibration issues with various pumps during commissioning. An independent opinion was required after multiple failed attempts by the OEM to fix the problem.
Specialized Vibration Testing On A Water Purification Plant With High Vibration
A construction firm needed help identifying potential issues with future pump motor replacements at a water purification plant. MSI was called to conduct specialized vibration testing on the current units and to predict how a motor change and future variable frequency drive operation (VFD) would impact the system.
CO2 Absorber Column Vibration Problem Resolution
MSI was contracted by a customer to investigate the source of high displacement vibration at the top of an absorber column (220 feet tall and 13 feet diameter) at low frequency and high displacement (6 inches displacement peak-peak). This high vibration caused the following issues:
Flood Event Simulation On a Stop Log
In this case study the customer required to implement a temporary stop log in a channel to lower water levels downstream in order to carry out construction work. To ensure the safety of the construction site the dynamic load (and subsequent structural integrity) on the temporary stop log had to be predicted for a worst case flood event.
Shock and Vibration Finite Element Analysis of a Printed Circuit Board
A commercial-off-the-shelf power supply was to be modified for military use. It was not obvious whether the existing design was robust enough to pass the military shock (MIL-S-901D) and vibration (MIL-S-167) test protocols. Before expensive prototypes were manufactured and tested, the system was to be analytically evaluated in an effort to identify weak points so that they could be redesigned.
Reciprocating Pump Torsional Analysis for OEM
MSI was contracted by a major domestic pump manufacturer to determine the torsional natural frequencies of a machinery train consisting of a five plunger reciprocating pump, a gear set including an intermediate shaft, and a VFD/motor driver.
Mitigating Resonance in a Sewage Plant
A vertical solids-handling pump in a sewage plant experienced a classical vibration problem. Whenever the pump was running, the pump, entire pedestal and nearby piping were shaking. The pump bearings had very limited life, and the mechanical seal would chronically leak. The owner claimed that it was a bad pump, and the OEM said that it was an installation problem.
Driveshaft Failures in Mine Slurry Raw Water Service Pumps Cured
A major pump OEM called on MSI to help resolve multiple pump driveshaft failures for an ore mining company in East Africa. At the company’s raw water pumping station, two of the three diesel driven vertical turbine pumps had sustained the catastrophic failures monthly.
Cryogenic Testing of a Hydraulic Pump
A hydraulic pump was failing in an aircraft critical safety related service, and a thorough performance evaluation was needed. The evaluation involved operating the pump on a test stand at very cold temperatures in an effort to simulate arctic operating conditions. MSI engineers and technicians were responsible for all aspects of the design and construction of the test rig and loop as well as performance of the test and collection of data.
Development of a Vacuum Blower
MSI was contracted by a major aerospace equipment supplier/manufacturer to design and prototype an FAA-approved vacuum generator for use on commercial aircraft. The design would be subject to strict FAA requirements and RTCA environmental conditions/test procedures for airborne equipment.
Aeroderivative Gas Turbine and Gearbox / Genset
MSI was called on behalf of a customer who had seen a large increase in the vibration levels of a particular Gas Turbine Generator Set being used to supply power to a large pharmaceutical facility. The increase in vibration levels was serious enough to warrant shutdown. This power facility was used to meet much of the electrical power needs of the entire complex and any loss of generating capacity translated straight into increased electrical operating costs .
Identifying Resonance In A Feed Pump: Modal Analysis
A Northeastern power plant had experienced chronic boiler feed pump failures for eight years, since the unit involved had been switched from base load to modulated load. The longest that the pump had been able to log between major rotor elements overhauls was five months.
Failure Analysis of a Compressor Impeller
MSI was contracted by a customer to investigate a series of blade cracking problems in a compressor impeller. An FEA model of the impeller was created to perform a natural frequency modal analysis.
Solving a Below-ground VTP Resonance with Specialized Testing & Analysis
Two vertical turbine pumps (VTPs) with 45 ft. (13.72 m) long column assemblies installed in a nuclear facility were suffering from premature wearing of the line shaft bearings and shaft sleeves leading to frequent and costly repairs. MSI was contracted to successfully solve the problem.
Aeroderivative Gas Turbine Modifications to Solve a Problem
MSI was contracted to understand and help solve a high vibration problem on an aero-derivative gas turbine driven generator. Vibration levels as high as 1.75 in/s peak at 1x HP rotor running speed measured on the HP compressor had been reported at full load.
Dynamic Analysis of a Street Sweeper for the Manufacturer
To identify potential opportunities for early bearing failure, MSI performed experimental modal analysis (EMA) and operational deflection shape (ODS) tests on a prototype unit for the manufacturer. The results showed locations where increased stiffness would extend bearing life.
Design And Test Of An Axial Hydro Turbine
MSI was tasked with designing a subscale (1/6th ) axial hydro-turbine utilizing a belt system to drive a generator. The turbine rotor consisted of a CNC machined wheel with teeth machined on the shroud to utilize an industrial belt for transmitting power. A full turbine system from inlet to draft tube was designed and tested in Massachusetts.
Fluid-Structure-Interaction and Hydraulic Analysis of a Pelton Turbine
A comprehensive Fluid-Structure-Interaction and Hydraulic Analysis of a Pelton Turbine. A detailed analysis of dynamic stresses in the turbine wheel under impingement of the water jet is porivded. A novel CFD technique reveals detailed insights into the wet and dry windage losses during operation as well as prediction of cavitation formation.
Treatment Plant Pump Cavitation Causing Pump and Pipe Vibration
A county water treatment plant heard "cavitation-like noise" from their newly installed pumps and called MSI for help. Tests were conducted to see if damaging cavitation existed and how to best address the issue.
Wastewater Treatment Blower High Frequency Audible Tone
What do you do when you have a small blower that’s as loud as a thunderclap – all the time? In this interesting case, we present a comparison of motion amplified video along with accelerometer-based data acquisition to develop an Operating Deflection Shape (ODS) model, resolving a 120dB nuisance.
Resolving a Non-Clog Pump Problem via Specialized Testing and Analysis
MSI performed specialized testing on behalf of an engineering firm for newly installed horizontally oriented non-clog pumps in a return activated sludge (RAS) application. All four pumps/motor systems were operating at much higher than specified vibration levels with excessive noise. Braces had been previously installed prior to MSI’s involvement on a trial and error basis with little impact.
Centrifugal Compressor Impeller Strain Measurement via FM Telemetry
MSI worked closely with a major compressor OEM to specify, install and conduct strain gage testing of a centrifugal compressor impeller on the OEM test stand. MSI utilized its state-of-the-art FM telemetry system to transmit 5 simultaneous channels of data with each channel at either 5 or 10 kHz.
Plant Expansion / Revamp Evaluations
Mechanical Solutions, Inc. (MSI) provides plant operators and engineering firms with analysis services to validate how new or retrofitted machinery and plant configurations will perform to avoid post-installation issues once the system is installed and operational . This is referred to as a design assessment, and is relatively low-cost "insurance" against potential problems during commissioning or over the life of the machinery system. These same analysis techniques are also applied to understand and characterize problems, and design solutions for issues uncovered after installation or as equipment including support systems age.
Rerate of a Francis Hydro Turbine
MSI was tasked with evaluating a 1920s Francis style hydro-turbine runner in order to replace the aging original ones at a plant near the Hudson River in Upstate NY. A new blade design improved runner efficiency as well as decreased the blade count from 16 to 15, reducing the runner weight.
Ultra-Low Head Hydro Turbine Design Optimization
The customer approached MSI during the design phase of their project looking for assistance with improving an existing hydro turbine design for ultra-low head hydropower applications. The design incorporated unique elements not common in the industry, and presented several unique challenges.
Optimization of Hydro Turbine with CFD Modeling of Discharge
The hydro turbine discharge chamber was modelled using CFD to include backpressure which would change the power production of the turbine.
Pump System Seismic Structural Analysis: Building Vibration
Mechanical Solutions, Inc. (MSI) was contracted by a manufacturer to perform a seismic structural analysis on three identical large pump systems in a low-activity and high-activity nuclear waste treatment process. The scope of the analysis included the pressure containment casing, nozzle attachments, support system and driver. The pump systems were required to meet the specs of Seismic Category 1 (SC-1).
Oil Tanker Pumping Station Screw Pump Troubleshooting
Troubleshooting a new oil tanker pumping station in Colombia consisting of 4 screw pumps. Specialized testing revealed that piping natural frequencies were to blame.
Feed Pump and Pipe Strain Testing
A nuclear power plant was trying to understand why their new feed water pumps exhibited high vibration amplitude (1x rpm) at the drive end (DE), showed step changes in vibration over time, and demonstrated inconsistent results associated with the alignment before and after shut-downs.
Alarming Sounds from Wastewater Digester Complex Compressor Piping
MSI conducted specialized vibration testing of a digester complex compressor piping in the US-Midwest. The main purpose of the testing was to find the root cause for the elevated noise levels.
Unique Testing for Pipe Resonance in a Nuclear Power Plant
Bearings and seals were prematurely failing in a safety-related Decay Heat Removal Pump, which was a single-stage end-suction volute pump. Operating Deflection Shape (ODS) testing demonstrated that the direct reason for the reliability problems was that the pump casing was badly distorting dynamically, with a dominant frequency of impeller vane pass versus the casing’s single volute tongue.
Avoid Pump & Pipe Vibration Issues - Solids Handling Pump
An example demonstrating the impact of the piping in pre-installation natural frequency analysis. In this case, by determining the effect of the suction/discharge piping on the natural frequencies of the currently installed pumps, the importance of including this piping in future FEA analysis predictions for the new pumps could be quantified.
CFD Analysis To Resolve Suction Induced Vibration Problems
Mechanical Solutions, Inc. (MSI) was initially contracted to perform specialized testing to quantify the level of flow instability in a Residual Heat Removal (RHR) pump system by the nuclear power plant owner. The task was to perform a CFD analysis of the existing double suction pump inlet, and to make recommendations for improvement with regard to flow-induced vibrations at low volumetric flow rates.
Stress Analysis of a Cardiovascular Stent
A manufacturer of cardiovascular stents developed a new design that required FDA approval before it could be sold in the United States. In order to obtain this approval it had to be shown that the stent could withstand the balloon expansion process without developing any cracks.
Root Cause Analysis (RCA) of Pump Rotor Failures
Impact testing was used to determine the reasons for three failures of a hydrocarbon cracking pump which was critical to a diesel fuel production process at a major California refinery. Each failure closed down or severely curtailed fuel production at the refinery, at an average cost of about $3/4 million per day.
Resolving a Sewage Pump Problem via Specialized Testing and Analysis
Based on MSI’s thorough testing, which included Experimental Modal Analysis (EMA), Operating Deflection Shape (ODS), and dynamic pressure testing, the problem root cause was determined to be a combination of the following factors:
Some Applications of Experimental Modal Analysis (EMA)
Three examples of how MSI engineers used Experimental Modal Analysis (EMA) to solve complicated vibration issues in rotating machinery systems.
Aeroderivative Gas Turbine Natural Frequency Excited By Imbalance
MSI conducted vibration testing of an aero derivative gas turbine on the west coast of the United States. The unit had been reported to have high vibration levels (2 in/s peak) at the HP compressor speed at maximum operational load (45MW).
Pre-Commission Analysis of Fin Fan Oil Cooler at a Petroleum Refinery
Execution of an experimental modal analysis which revealed potential resonance issues on a fin fan oil cooler before commissioning at a petroleum refinery. A finite element analysis helped develop a fix before the unit was ever started.
Commissioning a 425 MW Steam Turbine
MSI was called on behalf of an engineering construction firm building a new power plant in the Southern Hemisphere. The plant was only weeks away from the commissioning deadline, after which hundreds of thousands of US$ per day liquidated damages would be due.
Analysis of Multiple Hydro Turbines in a Parallel Array
Interest is increasing in the abundance of low head and ultra-low head hydropower opportunities. Given the limited power available from a single turbine in these circumstances, MSI was asked to model and analyze the performance of several hydro turbines operating in parallel.
Pipe Strain Causing Pump Vibration
Mechanical Solutions, Inc. (MSI) was contracted by a coal power electricity generation plant to perform thorough and specialized vibration testing of the main turbine driven boiler feed pump (TDBFP). It was previously reported that for several years, high shaft vibration had been detected at the pump inboard bearing (IBB), but mostly in the X direction. The vibration appeared to be proportional to the load of the plant and sensitive to the alignment. However, no apparent damage had been detected on the bearing or shaft journal.
Cavitation Assessment on Large Double-Suction Pumps
Challenge: Apply a new non-intrusive test method for quantifying the amount of damage caused by cavitation.
Resolving Vertical Pump Lineshaft Failures
MSI was contracted by a major petrochemical company to determine the reasons for chronic lineshaft failures in some 100 foot (30 meter) long vertical pumps, in service on an offshore oil platform. The natural frequencies predicted by the model, and their associated mode shapes, were to be evaluated for possible participation in the failures.
Stripper Tower & Associated Pipe Vibration Problem Solved
MSI conducted vibration and strain testing of a rerated CO2 stripper tower piping in the US-Mideast on December 2015. The main purpose of the testing was to detect the cause of fretting on newly installed piping at an elevation of 180’.
Seismic Analysis of a Vertical Turbine Pump
A nuclear power company purchased several new service water vertical turbine pumps for their power plant. As for all new nuclear installations, it needed to be shown that these pumps could withstand a standardized earthquake loading without structural failure.
Aeroderivative Gas Turbine Vibration Problem at Idle Conditions
A 22 MW aero-derivative gas turbine in peak generation service at a combined cycle plant had a rigid power turbine-to-generator coupling replaced with a flexible diaphragm coupling. Following the modification, high vibration was detected at the power turbine section of the unit, only at idle speed.
Ammonia Recip Compressor Pipe Vibration Problem Solved
Excessive motion by the discharge piping of a petrochemical ammonia reciprocating compressor startled the operators. MSI was tasked with finding the root cause and suggesting a fix.
Vibration Acceptance Testing Avoided Long Term Reliability Issues
Vibration Acceptance Testing avoided long term reliability issues and lowered the risk of vibration problems at commissioning and over the life of the plant with a properly specified and performed acceptance test including an experimental modal analysis (impact) test.
Fatigue Analysis of a Spinal Implant
A manufacturer of spinal implant systems had developed a new external-fixation clamping device to the stage that it was ready to undergo required compression-fatigue testing. Shortly before the testing commenced, the company requested that MSI predict through finite element analysis where the system initially would fail, and at what magnitudes of load.
Simulating the Performance of a Spinal Implant
A manufacturer of an innovative spinal implant approached MSI for help in assessing the implant’s structural integrity. Of concern was not only the ability of the implant to withstand the forces during deployment, but also to withstand the in vivo physiologic loading.
Solving a Forced Draft Fan Problem
Mechanical Solutions, Inc. (MSI) was contracted by a paper mill to solve excessive vibration problems on Induced-Draft and Forced-Draft fans and their respective drive trains. This case history discusses the motor driven FD fan problem and solution.
De-tuning Reed Frequencies in a Vertical Turbine Pump
MSI completed finite element vibration analysis of an automotive company’s proposed VTP installation. Analysis of the originally designed system indicated that there was a strong probability of resonant lateral vibration, in which the first “reed” frequency of the pump/motor/floor as a combined system would be driven by the 1200 RPM running speed.
Cavitation Surge and Acoustic Resonance
A nuclear power plant experienced chronic excessive sub-synchronous vibrations in their A and C Residual Heat Removal (RHR) pumps. This vibration became particularly large when Pump C operated at low flow rates, while Pump A was not operating. At this condition, vibration of both pumps was substantial, with Pump A (not operating) vibration levels greater than those of the operating Pump C.
VTP Gear Problem with Vibration Absorbers
Mechanical Solutions, Inc. (MSI) was contracted to solve excessive vibration problems on four newly installed 3-stage vertical turbine pumps at a fire pump station. All of the units are driven by diesel engines with a right-angle gear operating at constant speed (28.75 Hz).
Induced Draft Fan Gearbox Problem
Mechanical Solutions, Inc. (MSI) was contracted to solve excessive vibration problems on Induced-Draft and Forced-Draft fans and their respective drive trains. The fans were used in a paper mill. This case history discusses the ID fan/gear problem and solution. Another case study entitled “Solving a Forced Draft Fan Problem” presents information about the motor driven FD fan issue.
Determine Optimal Bucket Count for Pelton Hydro Turbine
How many buckets should a Pelton hydro turbine have? That was the question posed by the customer. MSI created a computational fluid dynamics (CFD) model to determine the optimal torque and power output considering two different configurations.
Acceptance Criteria For Your Sump Pump With Our Optimized Inlet Piping Designs
This is a Pump Inlet Design Optimization Study for a split case pump inlet. MSI was contracted to reconfigure the pump inlet piping in constraint space in order to meet Hydraulic Institute Acceptance Criteria.
Using Time Averaged Pulsing to Diagnose Critical Speeds of Rotating Machinery
A special experimental modal analysis technique, TAP™ (acronym for Time Averaged Pulsing), has been developed by MSI’s engineers. TAP™ can effectively determine critical speeds of all rotating machinery under operating conditions, so that they can be “bump” tested for natural frequencies, without shutting them down.
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